The present invention relates to electropneumatic brake control on a train and more specifically to the electronic portion of the trainline controller.
Electropneumatic brake control valves are well known in the passenger railroad art and the mass transit railroad art. Because the trains are short and are not involved generally in a mix and match at an interchange of different equipment, the ability to provide pneumatic and electrical control throughout the train has been readily available in the passenger and the mass transit systems. In freight trains, the trains may involve as much as 100 cars stretching over one mile or more. The individual cars may lay idle in harsh environments for up to a year without use. Also, because of the long distance they travel, the cars are continuously moved from one consist to another as it travels to its destination. Thus, the use of electropneumatic-pneumatic valves in the freight trains has been very limited.
A prior art system with electropneumatic train brake controls is illustrated in FIG. 1. An operator control stand 10 generally has a pair of handles to control the train braking. It controls a brake pipe controller 12 which controls the brake pipe 14 running throughout the train. It also includes a trainline controller 16 with power source 17 which controls the trainline 18 which is a power line as well as an electrical communication line. The control stand 10, the brake pipe controller 12 and the trainline controller 16 are located in the locomotive.
Each car includes a car control device 20 having a car ID module 22 and a sensor 24 connected to the trainline 18. The pneumatic portion of the car brakes include a brake cylinder 26, a reservoir 28 and a vent valve 29. The car control device 20 is also connected to the brake pipe 14 and the trainline 18. The brake pipe controller 12 is available from New York Air Brake Corporation as CCBII® and described in U.S. Pat. No. 6,098,006 to Sherwood et al. The trainline controller 16 and the CCD 20 are also available from New York Air Brake as a product known as EP60®. The car control device 20 is described in U.S. Pat. No. 5,967,620 to Truglio et al and U.S. Pat. No. 6,049,296 to Lumbis et al. Each of these patents and products are incorporated herein as necessary for the understanding of the present patent.
The trainline controller 16 is shown in detail in FIG. 2. The control stand 10 includes EP brake controller 30 and an operator interface unit or display 31 which are connected to a trainline communication controller 40. The trainline communication controller 40 is connected to the trainline 18 and receives 75 volts DC from the locomotive battery. It is also connected to the locomotive systems 32. The locomotive control 16 also includes a trainline power controller 50 connected to the trainline 18. It is also connected to 75 volts DC from the locomotive as well as the trainline power supply 38. The trainline power supply 38 provides all of the voltage necessary for operation of the electronics of the trainline power controller as well as the trainline 18. The 230 volts are applied to the trainline 18 in the normal operational mode. The 24 volts are the volts that is applied to the trainline 18 during synchronization.
The example illustrated in FIG. 2 is for a lead locomotive and a trailing locomotive. The trainlines between the locomotives are connected by EP trainline connectors 34. The leading EP line connector 34 has a head end termination HETT 36 terminating the trainline. The trainline communications controller 40 controls the trainline and communication and the power through the trainline power controller 50. Although the trainline power controller 50 and the trainline power supply 30 are shown in a second locomotive, they may also be located in the leading locomotive. Also, it is anticipated that all of the locomotives will have a trainline communication controller and a trainline power line controller therein. Using multiple power sources to power the trainline is described in U.S. Pat. No. 5,907,193 to Lumbis. Testing the trainline before powering up is also described in U.S. Pat. No. 5,673,876 to Lumbis et al.
The present invention is improvements in the trainline controller electronics. It includes a method for testing a signal quality for each node in the wire network on the train. This method includes commanding each node to be in a receiving node followed by commanding each node, one at a time, to transmit a calibration signal. Then, a determination is made of the quality of the calibration signals as function of the length of the transmission path on the wire. A system to perform this method includes a transceiver and a level sensor circuit connected to the trainline. A controller connected to the transceiver and level sensor controls the sending of the commands by the transceiver to each node and receives signals from the level sensor circuit. The transceiver and level sensor circuits are connected to the trainline by a common transformer. The level sensor circuit includes a filter and signal conditioning circuits. The filter may have a variable gain set by the controller. The signal conditioning circuit may include a rectifier and peak detector. It may also includes an analog to digital converter connecting the peak detector to the controller. The level sensor circuit may include a sensor control to store the signals from the signal conditioning circuit and send it to the controller. The sensor control may signal the controller that a conditioned calibration signal is ready and the controller requests transmission of the condition calibration signal. The sensor control may detect the presence of the calibration signal and activates the signal conditioning circuit.
The trainline communication controller on a locomotive and a wired network with the nodes in the car may include a transceiver and a signal detector connected to the trainline. A head end termination circuit is connected to the trainline at a common node with the signal detector. The controller is connected to the transceiver and the signal detector. This signal detector may include a transceiver connected to the trainline which detects the presence of a transmission packet. A multiplexer may be included which connects the signal detector to a front end and a rear end termination circuits. The detector may be connected to the junction by inductors and a rectifying bridge.
A method is provided for identifying stuck-on transmitting of a transceiver in a train network where the transceiver draws a first current for transmitting and a second car for receiving. The method includes sensing the current drawn by the transceiver and determine if the sensor current is between the first and second currents. Finally, a stuck-on detector is identified if the sensed current is determined to be between the first and second currents for more than a preset amount of time. The current can be sensed using a current mirror and the determining is performed by a comparator connected to the current. The identifying can be performed by a microprocessor which measures the time and identifies the stuck-on transmitter. The microprocessor may also disable a transmitter when identified is stucked on.
A transceiver control circuit may also be provided to perform the method and would include a current sensor, a comparator, and a timer. A controller identifies a stuck-on transmitter when the amount of time, the sensor current is determined to be between the first and second currents, is more than a preset amount of time. The current sensor includes a current mirror contact connected to the receiver and comparator. Also, the timer and the controller may be in a microprocessor. The controller disables a transmitter when identified as stuck-on. This is performed by providing a disable signal at the reset terminal of the transceiver. A reset circuit is connected to the reset terminal of the transceiver and the controller.
Other objects, aspects and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.